//https://leetcode.cn/problems/add-binary/

class Solution
{
public:
	string addBinary(string a, string b)
	{
		string ret;
		int cur1 = a.size() - 1, cur2 = b.size() - 1, t = 0;
		while (cur1 >= 0 || cur2 >= 0 || t)
		{
			if (cur1 >= 0) t += a[cur1--] - '0';
			if (cur2 >= 0) t += b[cur2--] - '0';
			ret += t % 2 + '0';
			t /= 2;
		}
		reverse(ret.begin(), ret.end());
		return ret;
	}
};